pcf2129a NXP Semiconductors, pcf2129a Datasheet - Page 18
pcf2129a
Manufacturer Part Number
pcf2129a
Description
Integrated Rtc, Tcxo And Quartz Crystal
Manufacturer
NXP Semiconductors
Datasheet
1.PCF2129A.pdf
(68 pages)
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
pcf2129aT
Manufacturer:
NXP/恩智浦
Quantity:
20 000
Company:
Part Number:
pcf2129aT/1
Manufacturer:
NXP
Quantity:
12 246
Part Number:
pcf2129aT/1,518
Manufacturer:
NXP/恩智浦
Quantity:
20 000
Company:
Part Number:
pcf2129aT/1Ј¬512
Manufacturer:
PH3
Quantity:
3 040
Part Number:
pcf2129aT/2,518
Manufacturer:
NXP/恩智浦
Quantity:
20 000
NXP Semiconductors
PCF2129A_1
Product data sheet
8.5.3 Battery low detection function
The output pin BBS can be used as a supply for battery backup devices such as SRAM
(see
V
The PCF2129A has a battery low detection circuit which monitors the status of the battery
V
When V
(register Control_3) is set to indicate that the battery is low and that it must be replaced. A
low battery will not ensure data integrity during periods of backup battery operation.
Monitoring of the battery voltage also occurs during battery operation.
When V
Figure
1. The battery low flag BLF is set logic 1.
2. An interrupt is generated if the control bit BLIE (register Control_3) is enabled
3. The flag BLF remains logic 1 until the battery is replaced. BLF cannot be cleared
Fig 8.
BBS
BAT
V
DD
V
(see
using the interface. It is cleared automatically by the battery low detection circuit when
the battery is replaced.
(= 2.5 V)
th(bat)low
.
Ref. 3
= V
is driven from V
V
8):
BLF
BBS
BAT
INT
BAT
BAT
Section
Battery low detection behavior with bit BLIE logic 1 (enabled)
“AN10857”). For this case,
drops below the threshold value V
drops below the threshold value V
8.12.7).
DD
Rev. 01 — 13 January 2010
.
Figure 7
internal power supply (= V
th(bat)low
Integrated RTC, TCXO and quartz crystal
th(bat)low
shows the typical driving capability when
V
BAT
, the following sequence occurs (see
(typically 2.5 V) the BLF flag
BBS
)
PCF2129A
© NXP B.V. 2010. All rights reserved.
001aaj322
18 of 68